This application claims the priority of German application 101 29 916.8, filed in Germany on Jun. 21, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention is based on an arrangement for fastening an exhaust gas turbocharger to an exhaust gas manifold of an internal-combustion engine.
From German Patent Document DE-AS 1 909 424 or U.S. Patent Document U.S. Pat. No. 4,318,273, internal-combustion engines are known in the case of which an exhaust gas turbocharger is flanged to the exhaust gas manifold, which exhaust gas turbocharger, in a known manner, utilizes the energy of the exhaust gas for delivering the fresh gases into the cylinders. For the exhaust-gas-side linking and fastening of the exhaust gas turbocharger to the exhaust gas manifold, the two components are provided with a flange, which are both connected by a nut-screw connection. As an alternative, threaded openings may also be made in one of the two flanges, in which threaded openings, fastening screws are received.
However, in the case of such a flange fastening, the access to the fastening screws and fastening nuts respectively may be problematic because the clearances on both flange sides are often not sufficient for the tools, for example, the wrenches or short box spanners.
It is therefore an object of the invention to develop an arrangement for the fastening of the exhaust gas turbocharger to the exhaust gas manifold of the internal-combustion engine, in the case of which a simple and easily accessible mounting or demounting of the exhaust gas turbocharger is permitted.
This object is achieved according to certain preferred embodiments of the invention by providing an arrangement for fastening an exhaust gas turbocharger to an exhaust gas manifold of an internal-combustion engine, having a manifold flange provided at the exhaust gas manifold, on which manifold flange an exhaust gas turbocharger can be fastened which is also provided with a flange surface, wherein the manifold flange is provided on one side of the exhaust gas manifold and is connected with sleeves leading to an opposite side of the exhaust gas manifold, in which sleeves fastening screws are guided for the fastening of the exhaust gas turbocharger.
By means of sleeves arranged at the flange of the exhaust gas manifold, the mounting plane for the fastening screws is displaced to the other side of the exhaust gas manifold, on which a sufficient mounting clearance is ensured. As a result, the exhaust gas turbocharger can be mounted rapidly and easily, and the use of automated screwing tools is permitted.
Other advantageous embodiments and improvements of the arrangement according to the invention are described herein and in the claims.
According to certain preferred embodiments of the invention the sleeves advantageously reach through the exhaust gas manifold pipe and are connected with the latter on a top side preferably by means of welding.
According to certain preferred embodiments of the invention for linking the sleeves to the flange of the exhaust gas manifold, the flange is provided with fastening openings, into which a fastening connection piece of the sleeves engages, the sleeves being connected with the exhaust gas manifold flange in a substance-locking manner.
The exhaust gas manifold is advantageously constructed as a double pipe according to certain preferred embodiments of the invention, the sleeves reaching through the outer pipe of the exhaust gas manifold. As a result of the displacement of the mounting plane by way of the course of the gas-carrying inner pipes, the required cross-sections of the inner pipes can be implemented while the space requirement for the exterior geometry of the exhaust gas manifold is minimized. Because of the fact that the sleeves are arranged in the air gap of the exhaust gas manifold created by the double pipe, a thermal decoupling of the sleeves from the hot exhaust gases takes place so that the weld seam points in the area of the sleeves as well as the screwed connection are less stressed by temperature.
According to certain preferred embodiments of the invention, the materials used for the fastening screws and the sleeves are coordinated such with respect to their coefficients of thermal expansion that a durable screwed connection can be achieved without an additional screw locking. A tempering steel, for example, can be used as the screw material, while special steel can be used as the sleeve material. As a result of the selection of such a sleeve material, the weldability with the outer shell of the exhaust gas manifold is simultaneously ensured.
According to certain preferred embodiments of the invention, the openings provided in the fastening flange of the exhaust gas turbocharger are provided with an internal thread in which the external thread of the fastening screws is received.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.